20 - 30 %
||Kudva R, Denks K, Kuhn P, Vogt A, Müller M, Koch HG. Protein translocation across the inner membrane of Gram-negative bacteria: the Sec and Tat dependent protein transport pathways. Res Microbiol. 2013 Jul-Aug164(6):505-34. doi: 10.1016/j.resmic.2013.03.016 p.505 left columnPubMed ID23567322
||Pugsley, A.P., 1993. The complete general secretory pathway in Gram-negative bacteria. Microbiol. Rev. 57, 50. AND Holland, I.B., 2010. The extraordinary diversity of bacterial protein secretion mechanisms. Methods Mol. Biol. 619, 1e20 DOI: 10.1007/978-1-60327-412-8_1PubMed ID8096622, 20419401
||P.505 left column: "One of the major challenges that prokaryotic and eukaryotic cells face is efficiently transporting proteins from their site of synthesis in the cytosol to their sites of function. As 20% - 30% (primary sources) of all proteins in bacterial cells are localised outside the cytosol, it is evident that protein transport is vital for the sustenance of cells. The inner membrane in Gram negative bacteria like Escherichia coli separates the cytosolic translation machinery from extra-cytosolic sections such as the periplasmic space or the outer membrane, forming a barrier against protein trafficking. To facilitate protein transport across this barrier, bacteria are equipped with membrane embedded protein transport systems that allow transport of proteins across the membrane into the periplasm or insertion of proteins into the membrane."